This invention relates to sponge mops, and more particularly to a type known as a butterfly mop wherein a self-wringing mechanism transversely folds and squeezes together two wing-like halves holding a detachable sponge.
Self-wringing sponge mops are well known, and many prior art designs exist. Generally a long tubular handle and a detachable sponge or sponge-like material are affixed to more or less opposite ends of a mop head assembly that includes a self-wringing mechanism. As is known, the long tubular handle extends the user""s reach, the detachable sponge allows for sponge replacement when needed, and the self-wringing mop head mechanism provides a useful and convenient means to quickly and repeatedly expel dirt and liquid from the sponge.
Butterfly type self-wringing mechanisms for sponge mops are also well know, wherein the detachable sponge is mounted on parallel wing-like halves that hinge transversely toward each other along axes more or less aligned with the mop handle. To squeeze the sponge various sliding or rotating mechanisms are known, or combinations thereof. Many show a pivoting yoke or lever that rotates around an axis positioned longitudinally above the sponge (and therefore perpendicular to the wing axes) that is moved back and forth past the wings to alternately squeeze and release them, thus expelling dirt and liquid from the sponge. Rollers may be mounted on the yoke to reduce sliding friction, and return springs may be attached to the hinged wings to assist their movement. Additionally, a movable handle mounted grip or lever may be attached to the yoke via a linkage, thus allowing the wringing mechanism to be actuated remotely. This helps prevent the user""s hands from becoming soiled by a wet and dirty sponge.
Despite the manufacturing cost and assembly complexity posed by the use of such elaborate wringing mechanisms as those enumerated above, butterfly mops have nevertheless proven successful over many years by dint of their compact size, efficient functionality, and ease of operation. More recently, the use of molded thermoplastic resin construction has helped reduce the cost and complexity of butterfly mops. For example, it is known that separate fasteners (e.g., screws and rivets) can be eliminated by integrating their function into molded parts. It is also known that resin parts need not be plated or painted to resist rust, unlike sheet steel components traditionally used. It is also known that separate butterfly wings formerly attached with hinge pins can be molded as integral parts of the mop head by interconnecting them with thin flexible webs known as living hinges. And it is also known that friction reducing rollers can be eliminated because certain molding resin have low friction coefficients (e.g., they slide easily against other surfaces).
U.S. Pat. No. 2,643,407 (Vosbikian) discloses a sponge mop with an early butterfly style wringing mechanism. The wringing mechanism requires at least eight separate parts, namely, a central body, two hinged wings, two hinge pins, a pivoting extractor lever, and two cone shaped rollers to reduce friction. In fact this invention is currently manufactured and sold as the Quickie Automatic Sponge Mop, but with at least five additional parts, namely, two wing return springs, a movable remote grip, a linkage connecting the extractor lever to the remote grip, and a rivet connecting the remote grip to the linkage. Thus, the wringing mechanism of this mop requires a total of at least thirteen individual parts.
In summary, the Vosbikian patent, as exemplified by the Quickie Automatic Sponge Mop, teaches a useful butterfly sponge mop design but requires many separate parts that increase its manufacturing cost and assembly complexity.
U.S. Pat. No. 4,044,419 (Robinson) discloses a sponge mop with an improved butterfly style wringing mechanism, wherein Quickie""s thirteen part construction described above has been reduces to just three, namely, a one piece central body with integrated wings, a one piece actuator lever with integrated grip, and a single return spring. First, Quickie""s five-piece wing assembly (central body, two wings, and two hinge pins) has been reduced to just one part, namely a central body with integrated wings. Injection molded thermoplastic resin construction allows the wings to integrally connect to the central body using thin flexible webs known as living hinges, thus eliminate the need for separate wings and hinge pins. Second, Quickie""s six-piece lever and grip assembly (lever, two rollers, grip, linkage, and rivet) has been reduced to a single part. The use of injection molded resin construction allows the elimination of separate rollers to reduce friction, and also allows the grip to be integrated into the lever. Relocation of the grip and lever to the upper side of the mop head moves the user""s hands away from the wet and dirty sponge, thus reducing the need for a remote grip, linkage, and rivet. Third, Quickie""s pair of wing return springs is replaced by a single spring passing across the central body to connect one wing to the other.
Certain problems are apparent on closer examination of the Robinson patent. First, it claims a mop head of two basic parts, but in fact it shows a third part, a wing return spring, that is required to return the wings to their in-line planar position. Extra parts add cost and complicate assembly. Second, the parallel actuator members that squeeze the sponge are generally unsupported or interconnected near where they squeeze the central portion of the sponge, and thus may deflect or twist outward and provide a less satisfactory wringing action, particularly with denser and less compressible sponge materials. Third, both molded parts require expensive die side actions to be molded as shown in the patent. The stiffening ribs around and across the outsides of the parallel members of the actuator cannot be molded except with large outwardly movable die side actions with elaborate matched parting lines. And at least one or more of the features described on the mop head (handle socket, actuator socket, or spring locating pins) will also require expensive die side actions.
In summary, the Robinson patent teaches useful improvements over the Vosbikian patent, but further improvements are possible, particularly with regard to making the molded parts less costly through more efficient geometry and fewer required die side actions.
The butterfly sponge mop according to my invention includes a pair of hinged wings integrally molded onto one end of an actuating lever. This lever pivots forward and back within an enclosed yoke. Moving the lever forward causes the wings to swing closed, thus squeezing a detachable sponge. Moving the lever back to its original position causes the wings to swing open, aided by the compression of the sponge. The wings are positively held in their open position by wing tabs that move in and out of corresponding pockets within the yoke as the actuating lever is moved forward and back. The lever continuously changes its mechanical force on the wings, such that initial forward movement closes the wings rapidly, while further forward movement produces a decreasing movement of the wings.
It is an object of my invention to provide a butterfly sponge mop that requires only two parts for the entire wringing mechanism, this being an improvement over the three part Robinson patent described above (e.g., two basic parts, plus a return spring). It is another object of my invention to provide a butterfly sponge mop with wing tabs that hold the wings in their open position, thus eliminating the need for wing return springs. It is another object of my invention to provide a butterfly mop wherein the yoke holding the actuating lever is of enclosed design, with unique girder geometry. It is another object of my invention to provide a butterfly mop wherein the yoke holding the actuating lever can be molded in a molding die with no side actions except one, and that one being of small size and simple geometry. It is a further object of my invention to provide a butterfly sponge mop wherein the actuating lever with its integrally molded wings can be molded in a molding die with no side actions whatsoever.